Technical Field
This invention relates generally to a self-contained in-ground geothermal generator. This invention also relates to the effective method of use of geothermal energy.
State of the Art
Geothermal is a renewable energy source made possible by the same tectonic activity that causes local earthquakes and the rising mountains. Geothermal is endless supply of energy from which we can generate power. The earth's rigged outer shell, the lithosphere, consisting of the crust and upper mantle, rests upon the hotter and more plastic region of the upper mantle, below the crust, called the asthenosphere. The thickness of the Earth's crust varies from a few miles to perhaps hundred fifty miles. Rock heated by magma deep below the surface boils water trapped in underground reservoirs—sometimes as hot as 700 degree F. Some of this hot geothermal water travels back up through faults and cracks and reaches the earth's surface as hot springs or geysers, but most of it stays deep underground, trapped in cracks and porous rock This natural collection of hot water is called a geothermal reservoir. We already enjoy some of this activity via natural hot springs.
Presently, wells are drilled into the geothermal reservoirs to bring the hot water to the surface. At geothermal power plants, this hot water is piped to the surface. Then, after removing silica, steam is created and used to spin turbines creating mechanical energy. The shaft from the turbines to the generator converts mechanical energy to electrical energy. The used geothermal water is then returned down an injection well into the reservoir to be reheated, to maintain pressure, and to sustain the reservoir.
There are three kinds of geothermal power plants. The kind we build depends on the temperatures and pressures of a reservoir.                1. A “dry” steam reservoir produces steam but very little water. The steam is piped directly into a “dry” steam power plant to provide the force to spin the turbine generator. The largest dry steam field in the world is The Geysers, about 90 miles north of San Francisco. Production of electricity started at The Geysers in 1960, at what has become the most successful alternative energy project in history.        2. A geothermal reservoir that produces mostly hot water is called a “hot water reservoir” and is used in a “flash” power plant. Water ranging in temperature from 300-700 degrees F. is brought up to the surface through the production well where, upon being released from the pressure of the deep reservoir, some of the water flashes into steam after removing silica in a ‘separator.’ The steam then powers the turbines.        3. A reservoir with temperatures between 250-360 degrees F. is not hot enough to flash enough steam but can still be used to produce electricity in a “binary” power plant. In a binary system the geothermal water is passed through a heat exchanger, where its heat is transferred into a second (binary) liquid, such as isopentane, that boils at a lower temperature than water. When heated, the binary liquid flashes to vapor, which, like steam, expands across and spins the turbine blades. The vapor is then condensed to a liquid and is reused repeatedly. In this closed loop cycle, there are no emissions to the air.        
It's also a proven, relatively clean energy source. More than 30 nations sitting in earthquake and volcanic zones have extensively used geothermal power for decades.
Existing use of geothermal energy is limited with location. Geothermal resources are limited to the “shallow” hydrothermal reservoirs at the crustal plate boundaries. Much of the world is underlain (3-6 miles down), by hot dry rock—no water, but lots of heat.
Presently, a cross the globe many countries are looking to the heat of hot rocks for future energy need. In areas of the world where steam is not as close to the surface as it is at the geysers, engineers are experimenting with process called “hot dry rock technology” or “Enhance Geothermal System” (EGS).
In hot dry rock geothermal technology there is no steam lock up in the hot rocks that exist down under the crust so scientist in the U.S.A., Japan, England, France, Germany, Belgium and Australia, have experimented with piping water into this deep hot rock to create more hydrothermal resources for use in geothermal power plants. The simplest hot dry rock power plant comprises one injection well and two production wells.
What they try to do is drill down an injection well into the rock and then inject down into the well, under pressure, what ever water source they happen to have on the surface, hoping that it will travel through cracks and fissures as an underground heat exchanger in the hot granite and provide underground reservoir and then drill more production wells around perimeter and try to recover that water and steam and pump it back to surface and then use it in a conventional or in a “binary” power plant.
The invention of the coal-burning steam engine revolutionized industrial production in the 18th c. and opened the way to the development of mechanized transport by rail and sea. The modern steam engine, using high-pressure superheated steam, remains a major source of electrical power and means of marine propulsion, though oil has replaced coil as the fuel in many installations and the reciprocating engine has given way to the steam turbines.
Modern wells, mostly used in oil industry and geothermal plants, drilled using rotary drills, can achieve lengths of over 38,000 feet (12 000 meters). The well is created by drilling a hole 5 to 30 inches (13-76 cm) in diameter into the earth. Drilling technology is improving every day.
Accordingly, there is a need in the field of geothermal energy for an apparatus and method for effectively using the enormous heat resources of the Earth's crust that are accessible by using current drilling technology.